A 34-year-old man has been arrested and charged with kidnapping a teenage girl in the US who returned home last week after vanishing nine months ago.

Nathaniel Kibby was arrested without incident at his New Hampshire home and was charged with felony kidnapping, authorities said.

Police allege Kibby knowingly confined Abigail "Abby" Hernandez, then 14, on October 9, sometime after she left Conway High School for her home. Abby returned home the night of July 20, but authorities have not explained the circumstances of her return.

Attorney General Joseph Foster said on Monday law enforcement officials have worked around the clock to determine the facts surrounding the girl's disappearance and return. He said Abby provided the police with details of her kidnapping sufficient to warrant Kibby's arrest.

Kibby is scheduled for arraignment on Tuesday at Conway District Court. It was not immediately known if Kibby has a lawyer. Foster said he will have a press briefing after the arraignment.

Abby's mother, Zenya Hernandez, said in a television interview on Monday she believes Abby, now 15, did not run away and didn't know the man believed to have driven off with her. Police released a sketch of him last week based on Abby's description.

Abby also issued a statement, which was posted on Facebook, thanking people who searched for her and saying she believes their hopes and prayers "played a major role in my release".

Zenya Hernandez told NBC's Today that when her daughter returned home, she was thin and pale and had "a look in her eyes I've never, ever seen before. And that's something that's haunting me, and I think will haunt me for the rest of my life."

The mother also said in the television interview that rumours that her daughter was pregnant aren't true.

Roger Lawrence, 66, who lives in the same mobile home park as Kibby, said he met him last summer while Kibby was walking his dog. He didn't know him well but exchanged pleasantries with him.

"He seemed to be nice, down to earth. He was very polite," Lawrence said.

Lawrence said he didn't see Kibby all winter, but saw him on Saturday, walking past his home to get his mail. He was shocked to hear of the arrest.

"No words can explain it. I was ready to wring his neck. I was very surprised," he said. "I was wondering what happened to that little girl myself, seeing it on the news, thinking, 'Where could she have gone?'"